The present invention relates to an apparatus, a method and a communication system for automatically transporting bulk data between places where there is no fixed-network line, and in particularly to a wireless data transport apparatus and a transport system of the same for intermediating a transport of the bulk data and an acknowledgement between a plurality of fixed stations with which a mobile station communicates in a wireless communication.
As a result of advancing technology, it has been progressed that a reliability of industrial products is improved, a failure frequency is reduced, and a time period by the time of occurring the failure becomes long. In contrast, in a condition where various products have been spread out on a global scale in these days, a time period by the time of specifying a failure place and of procuring parts to be used for a repair becomes also long when the failure occurs once. Consequently, a manager for the products has paid attention to find the failure soon.
In the past, the manager for the products has picked up an operation condition of the products and signs of the failure to then build up a system for notifying operation information of the products by using a wireless technique, such as a cellular phone, a satellite communication channel, etc.
In the case of places where there is no fixed network line, JP-A-2008-115554 discloses a system of transporting data by using the wireless communication.
A wireless communication system disclosed in the JP-A-2008-115554 provides a wireless communication device installed on a mining heavy machinery, a transport heavy machinery and an unloading area. The transport heavy machinery travels back and forth between the mining heavy machinery and the unloading area for transporting ores. The transport heavy machinery transports the ores, and also receives and stores mining operation information from the mining heavy machinery by using the wireless communication device. Thereafter, the transport heavy machinery arrives at the unloading area to then transmit the stored mining operation information by the wireless.
The transport heavy machinery requests a transmission of mining information to the mining heavy machinery by manual or automatic. In the manual, an operator of the transport heavy machinery recognizes the mining heavy machinery to enter an ID indicating the mining heavy machinery, which is disclosed in the JP-A-2008-115554. In the automatic, the operator of transport heavy machinery depresses a predetermined button to request a reply from the mining heavy machinery resided around the operator and the mining heavy machinery from which a strongest received field strength is replied is recognized as a communication partner, which is also disclosed therein.
As mentioned above, the wireless communication system in the JP-A-2008-115554 intermediates the transport heavy machinery between a mining site and the unloading area to send the mining operation information.
Further, JP-A-2006-148290 discloses a vehicle information collecting system for simply and steadily collecting vehicle information from vehicles traveling freely in a wide workplace in low cost.
In the vehicle information collecting system in the JP-A-2006-148290, a terminal device collects the vehicle information of between a plurality of vehicles and the terminal device by using a wireless LAN. The terminal device performs a broadcast transmission toward the vehicles to request a vehicle ID by using the wireless LAN. The vehicle transmits the own vehicle ID to the terminal device by the wireless LAN. The terminal device receives the vehicle ID to discriminate a target vehicle from which the information is acquired and perform a unicast transmission to request the vehicle information for the target vehicle from which the information is acquired by the wireless LAN.
When a target product is expensive and an availability ratio of the product is significantly effect on benefit and trust of the operator, it is important that the product failure should be previously predicted for economics and trust of enterprises. Consequently, a preventive maintenance technique has been paid attention to detect a failure sign.
For performing the preventive maintenance, a status indicating whether the product is normal or abnormal is notified and the operation information indicating a temperature inside the product and an operation time period is also notified, which is, however, sometimes insufficient. For a purpose of realizing the preventive maintenance, it is required that a control message inside the product to be targeted to the preventive maintenance and various pieces of sensor information to be used in the control are notified to a manager side. To this end, data amount to be notified becomes enormous, or it sometimes becomes several hundred megabytes (MB, mega is the 6th power of 10) per day as an example.
As mentioned above, an example to be notified the product data to the manager side has been existing, in the case of between the places where there is no fixed network line and between the products. A wireless network, such as a satellite network, cellular phone, etc. cannot be used for sending the bulk data due to the economic reason, it is therefore required to have a system of automatically retrieving data by making use of a self-administered wireless, such as wireless LAN. However, there are two points as large problem in the above-mentioned technique so that the bulk data extended to the several hundred MB per day is transmitted.
As a first problem, it cannot be performed that an appropriate product to be targeted to the preventive maintenance (for example, the wireless communication device of mining heavy machinery in JP-A-2008-115554) is mutually and automatically recognized with an appropriate mediator (for example, the wireless terminal device of transport heavy machinery in JP-A-2006-148290) to then transmit and receive necessary data one another, in the above-mentioned systems. Therefore, it is required that the communication partner is recognized frequently and efficiently with one another to transmit and receive the necessary data automatically so that the mediator receives the bulk data from the product.
However, in the JP-A-2006-148290, an operation requires that whether the operator selects the communication partner by manual or the operator resided around the mining heavy machinery depresses a button so that the communication partner is recognized. It is also required that the vehicle information as an instruction is given to the terminal device in advance, in the JP-A-2006-148290.
Further, it is required that a retransmission request corresponding to a data loss is received and data is also received from a number of the mediators so that the mediator receives the bulk data from the product to notify it to the manager side. However, there is no disclosure related to a data flow control in the JP-A-2008-115554 and JP-A-2006-148290.
A second problem of transmitting the bulk data is that a storage volume of product data becomes large, but there is no disclosure of a system for appropriately controlling a time period during which data is stored. For this reason, a data storage area for the product becomes excessive to therefore increase a cost. Or, a data storage area for the product becomes too small, therefore, there arises a problem that data is lost before communicating data necessary for the product.